32 Bit HDR Tutorial

So What’s New With 32?

What is a 32 Bit File?

So what are we actually talking about here? If you are familiar with HDR (high dynamic range) already, you’ll know that we use some software to merge multiple exposed images together to create what is called a “tonemapped” image (If you are new to HDR, check out the Getting Started page). Generally, the tonemapped file and most RAW photographs that you work with are 12-16 Bit files. What this really boils down to is the volume of information that is stored within a file. The more volume your file has, the more information you can pull out of it when developing. Makes sense.

The new process does something pretty radical. It completely bypasses the ‘tonemapping’ stage, and through some computer magic, takes your bracketed photos and combines them into one load of information file, that you can then develop like you would a RAW image right in Lightroom. This is pretty neat, as many HDR photographers know that there are limitations to the algorithms used in tonemapping.

Okay, I think that’s enough of the behind the scenes stuff here. Let’s move on to how to incorporate this new technique to your workflow.

What You Need

Lightroom 4.1 or later

Photoshop or Photomatix (new plugin link below)

Bracketed Photos – If you need more information about taking your bracketed photos, head over to the In the Field tutorial.

That’s it really. Both Photoshop’s HDR software and Photomatix have the ability to save your bracketed photos back to Lightroom as 32 Bit photos. For Photomatix users, you’ll need the new plugin found HERE.

Getting Started in Lightroom 4.1

First things first, whether you’re a Photoshop user or Photomatix user, the one thing you’ll need is to be using Lightroom 4.1 or later. Prior to that the software was not able to handle 32 Bit files. Also, depending on which one you are using, the interface will be slightly different. I’ll show both.

So here we are, in my Lightroom collection that I keep my “to develop” files. I’ve got three files highlighted that we will work on for this example. As you can see, there is a pretty dynamic range of light, mainly because of the back lighting of the tree. We don’t want to lose out on all that light information from these different levels, so it makes a good candidate for this process.

Using Photomatix

This is where the plan deviates a bit. For Photomatix users, right-click on the highlighted images (make sure you have all your brackets highlighted) move up to “Export” then to “Merge to 32-bit HDR”.

You’ll get a dialog box similar to what you’ve seen in Photomatix export plugins before, asking if you need to align photos, remove ghosts, noise reduction, etc. If you’ve used Photomatix before, you can skip on down to the Back in Lightroom section. If not, here are your options:

1) Align Images: Use this box if you shot handheld or believe there could have been any camera shake on your tripod

2) Remove Ghosts: If there are moving objects in your image, this might be a good option to check.

3) Reduce Noise: I haven’t noticed that 32 bit HDR adds a whole lot of noise to an image, so I have never checked this box. If you’re shooting at high ISO’s, though, it might help.

4) Rename Files: I add the suffix _32BIT so that I know which files in my library have been edited.

5) Scale Pixel Value: Leave this checked.

After choosing your options here, click on “Merge” and you’ll see this little dialog letting you know that the plugin is chugging along. That’s it, you never leave Lightroom. A new photo will magically appear in your folder!

In Photoshop

If you are a Photoshop user, the process is just slightly different. You’ll have your bracketed files selected, and right-click. Then move up to “Edit In”, then “Merge to HDR Pro in Photoshop”, similar to if you were going to tonemap the image in HDR Pro.

Photoshop will now open, as well as HDR Pro. This box will open up, with a funky looking version of your file, but instead of tonemapping now, make sure the Mode is set to 32 bit mode and just click “OK”.

Photoshop’s HDR Pro will do its thing, merging the files, and open a single layer file in Photoshop. All you do from there is a “File -> Save” (make sure that your default save settings are TIFF, otherwise do a ‘Save As…’ and choose TIFF as your output format) and we’re heading right back to Lightroom.

Back in Lightroom

Depending on what software you used before, the steps varied a little bit, but once you are back in Lightroom, it’s all the same again. And the best thing about all this? Now that we’re back in Lightroom, we can just develop this 32 bit file like any other file, but with one big difference, that there is a ton more light information saved in that one file. Below you can see my basic development settings for the two files that we looked at above.

That’s it! A quick export to merge your bracketed files, imported back to Lightroom, then it’s an easy effort to do some basic editing and you’re left with a great dynamic range available in your image.

Comparison to a Single Image

Here’s a before and after. The 32 bit file on the left, and the single exposure on the right, both with some Lightroom adjustments.

Comparisons to Tonemapped

Here’s an example of a file done in 32 bits vs a tonemapped image. On the left is the 32 bit file, and on the right is the same image tonemapped.

Parting Thoughts: Better or Worse?

Is a 32 Bit file better or worse than a tonemapped file? Well that is more up to you. A lot of people LOVE HDR, and the effect that tonemapping has on an image. It gives it a different look, a different feel. While I often go for a level of realism in my HDR images, I do like to push the boundaries a bit. I don’t think that doing HDR with the 32 Bit technique will yield the “HDR look” that a lot of folks are used to, but there are plenty of people who want a better solution to more dynamic range in their images. Will I replace my current techniques? No, not completely, but I consider this another tool that will be added to my workflow for certain images.

9 Comments

My LR4 Export screen does not have the 32bit option under the photomatix plug in. Am I missing an update or something here? A setting maybe? I updated all my programs and it’s still not there. Help please!

Here’s what I’m thinking, when you export to HDR pro, make sure that the little drop down window in the upper right corner says 32 bit and not 16 bit, then click ‘okay’. You don’t want to have any options for editing settings in HDR Pro.

Wyn, yep, you can definitely convert the 32bit file to a tif and delete the original. There is a couple of ways you can do it:
1) Open the 32 bit file in photoshop and save as a tif
2) Right click on the 32 bit file in lightroom, go to ‘export’, and export as a tif. I have this saved as a standard action so I don’t have to check any settings when I export.